Hello, this is my first post here after lurking long enough to know somebody here will have an answer. This weekend I came home and noticed a strong smell, which turned out to be the last pound or so of powder in an eight pound container which had gone bad. I set it outside. About two hours later the fire department knocked on my door and asked about the smoke the neighbors saw. The keg looked like the powder had burned on the inside and melted the plastic jug. It wasn’t a big fire because although the plastic had melted down to a pancake, the label was not burned and is still readable. I knew powder could go bad but didn’t know spontaneous combustion was possible. Any ideas on what happened?